Department of Food Science and Technology, Robert Mondavi Institute for Wine and Food Science, University of California, Davis, Davis, California, USA.
Foods for Health Institute, University of California, Davis, Davis, California, USA.
Appl Environ Microbiol. 2020 Dec 17;87(1). doi: 10.1128/AEM.01738-20.
Prebiotics are increasingly examined for their ability to modulate the neonate gut microbiota of livestock, and products such as inulin are commonly added to milk replacer used in calving. However, the ability of specific members of the bovine neonate microbiota to respond to inulin remains to be determined, particularly among indigenous lactobacilli and bifidobacteria, beneficial genera commonly enriched by inulin. Screening of and isolates obtained from fresh feces of dairy calves revealed that lactobacilli had a higher prevalence of inulin fermentation capacity (58%) than bifidobacteria (17%). Several (synonym ) isolates exhibited vigorous growth on, and complete degradation of, inulin; however, the phenotype was strain specific. The most vigorous inulin-fermenting strain, YZ050, readily degraded long-chain inulin not consumed by bifidobacterial isolates. Comparative genomic analysis of both fermenter and nonfermenter strains indicated that strain YZ050 encodes an inulinase homolog, previously linked to extracellular degradation of long-chain inulin in , that was strongly induced during growth on inulin. Inulin catabolism by YZ050 also generates extracellular fructose, which can cross-feed other non-inulin-fermenting lactic acid bacteria isolated from the same bovine feces. The presence of specific inulin-responsive bacterial strains within calf gut microbiome provides a mechanistic rationale for enrichment of specific lactobacilli and creates a foundation for future synbiotic applications in dairy calves aimed at improving health in early life. The gut microbiome plays an important role in animal health and is increasingly recognized as a target for diet-based manipulation. Inulin is a common prebiotic routinely added to animal feeds; however, the mechanism of inulin consumption by specific beneficial taxa in livestock is ill defined. In this study, we examined and isolates from calves fed inulin-containing milk replacer and characterized specific strains that robustly consume long-chain inulin. In particular, novel strain YZ050 consumed inulin via an extracellular fructosidase, resulting in complete consumption of all long-chain inulin. Inulin catabolism resulted in temporal release of extracellular fructose, which can promote growth of other non-inulin-consuming strains of lactic acid bacteria. This work provides the mechanistic insight needed to purposely modulate the calf gut microbiome via the establishment of networks of beneficial microbes linked to specific prebiotics.
越来越多的研究表明,益生元能够调节家畜新生儿肠道微生物群,并且像菊粉这样的产品通常被添加到用于产犊的代乳料中。然而,特定的牛新生儿微生物群成员对菊粉的反应能力仍有待确定,特别是在本土乳杆菌和双歧杆菌中,这些有益菌通常会被菊粉富集。从奶牛犊牛新鲜粪便中分离得到的 和 分离物的筛选表明,乳杆菌对菊粉发酵能力的出现率(58%)高于双歧杆菌(17%)。几个 (同义词)分离物在菊粉上表现出旺盛的生长,并完全降解了菊粉;然而,这种表型是菌株特异性的。最旺盛的菊粉发酵菌株 YZ050 很容易降解双歧杆菌分离物未消耗的长链菊粉。对两种 发酵菌和非发酵菌的比较基因组分析表明,菌株 YZ050 编码一种菊粉酶同源物,该同源物先前与 在体外降解长链菊粉有关,在菊粉生长过程中强烈诱导。YZ050 对菊粉的代谢也会产生胞外果糖,胞外果糖可以交叉喂养从同一牛粪便中分离出来的其他非菊粉发酵的乳酸菌。特定的对菊粉有反应的细菌菌株存在于小牛肠道微生物群中,为特定乳杆菌的富集提供了一种机制性的理由,并为未来旨在改善早期生活健康的奶牛小牛共生应用创造了基础。肠道微生物群在动物健康中起着重要作用,并且越来越被认为是基于饮食的操纵的目标。菊粉是一种常见的益生元,通常添加到动物饲料中;然而,特定有益菌群在牲畜中消耗菊粉的机制尚不清楚。在这项研究中,我们研究了在食用含菊粉的代乳料的小牛中分离得到的 和 分离物,并对能够强烈消耗长链菊粉的特定菌株进行了特征描述。特别是,新型 菌株 YZ050 通过胞外果糖苷酶消耗菊粉,导致所有长链菊粉完全消耗。菊粉代谢会导致胞外果糖的短暂释放,从而促进其他非菊粉消耗的乳酸菌菌株的生长。这项工作提供了通过建立与特定益生元相关的有益微生物网络来有目的地调节小牛肠道微生物组所需的机制见解。